1972 6hp johnson- how to determine if waterpump is working

[ctswf]

Hi,
I just got my 1972 6hp johnson model 6R72D running well with a carb cleaning thanks to the help of the great people of this site.

Its running in a bucket of water, what should be coming out of the exhaust? air and some moisture, mist, or a noticeable spray of water?

I wanted to take a quick test run before diving deeper into repair but not sure If I should do the water pump/impeller first.

there is air but seems not much moisture, hard to tell but there is certainly no noticeable water spray coming out anywhere

thanks

 

[AlTn]

water level in bucket should be high enough to submerge the lower unit completely....personally I bring it up to ~ 4 in. below the exhaust relief "nostrils" on the exhaust housing, tho' not sure it needs to be that high, but it approximates the water level the motor has when attached to the boat, loaded and at rest on the river. You should see a goodly amount of water spray mixed with exhaust coming from the exhaust relief holes at idle. Google leeroy's ramblings for his write up on this series of engines for some useful info as well.

 

[racerone]

Water should be 6" above the pump !!!---These pumps ( new or worn ) are not self priming.---Install a new impeller if you are not sure how old it is.---Checked the thermostat ?---Last ones I looked at were stuck open.

 

[rocket rich]

what will I see if the thermostat is stuck open---stuck closed it would cycle on what???

 

[ctswf]

what will I see if the thermostat is stuck open---stuck closed it would cycle on what???

I would like to know this also.

thanks for the info here. I changed the bucket and raised the water level. leeroys ramblings also mentions you might have to kick it in to forward. I do indeed spray water out. although I'm sure I should do the impeller soon anyway.

thanks!

 

[AlTn]

open is easy..remove the thermostat

 

[racerone]

??????---When motor is running the water pump operates.---Not sure where these tall tales about it needing to be in gear come from ?

 

[gm280]

Since the water pump impellor is installed directly on the drive shaft attached to the crankshaft, every time the engine turns, the water impellor turns as well. There is no gear to engage to make the water pump impellor turn...

 

[Vic.S]

??????---When motor is running the water pump operates.---Not sure where these tall tales about it needing to be in gear come from ?

They come perhaps from this passage in Leeroy's Ramblings

These motors main water supply to the water pump comes from a screened tube right behind the prop in the exhaust outlet. Water is forced into the screened intake to the water pump by the prop thrust. Some users report that when running these motors in a barrel, (usually a small one) that the prop has to be installed and usually in gear as apparently they need to get more water pushed to the water pump by the prop to get enough to cool when running at over an idle.

 

[F_R]

If you have any doubt about the water pump----change it!!!! It may be pumping today, but may shed all it's vanes or spin a hub tomorrow. When you have a known good pump in there, you don't have to be worrying about it and can relax and enjoy the ride.

 

[racerone]

Leroy rambles on and on !!!!